Technician Handbook 031 Maintenance and General Service Exhaust Ventilation When working with the engine running, make sure to provide ventilation for exhaust fumes in the workshop. Exhaust fumes contain carbon monoxide. Carbon monoxide is an odorless and colorless gas that can be harmful or fatal when inhaled in sufficient quantity. For your safety and the safety of others, know how to correctly use the ventilation equipment in your shop, and use proper ventilation procedures whenever needed. 24 Technical Training